The invention is applicable to the field of fuel management on reactor cores of pressurized water reactors, and provides a refueling method for fuel assemblies of a reactor core of a PWR (pressurized water reactor) nuclear power plant. The method comprises: classifying the fuel assemblies of the reactor core into three enrichment areas according to different enrichment degrees; in an initial cycle, respectively adding 8, 12 and 16 burnable poison rods into the fuel assemblies, and according to a cycle length of 18 months, placing the fuel assemblies with high enrichment degree outside the reactor core, and placing the fuel assemblies with low enrichment degree in the reactor core, wherein the enrichment degrees of the fuel assemblies of an initial reactor core are respectively 3.9%, 3.1% and 2.0%; and in subsequent cycles, starting from a second cycle, and rapidly transitioning the subsequent cycles to an equilibrium cycle according to an enrichment degree of 4.45%, wherein a mode of 18-month refueling is adopted, and the fuel assemblies of 1 / 2-1 / 3 of the reactor core are replaced every time; meanwhile, placing the new fuel assemblies in the reactor core, and placing the fuel assemblies which are burned outside the reactor core. By using the refueling method provided by the invention, the cycle period is extended, the fuel consumption is improved, and the purpose of completely low neutron leak loading is achieved in the subsequent cycles.